One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10,14,18)(11,17,15,12)(13,21,23,16)(19,20,22,24)(2,5)(3,7)(9,11)(10,12)(13,22)(14,15)(16,24)(17,18)(19,23)(20,21)(26,30)(31,37)(32,38)(39,40) involution — undirected(1,2,4,5)(3,6,7,8)(9,12)(10,15)(11,18)(13,20)(14,17)(16,22)(19,21)(23,24)(25,26)(27,31)(28,32)(29,30)(33,39)(34,37)(35,40)(36,38)(1,3)(2,6)(4,7)(5,8)(9,13,14,23)(10,16,18,21)(11,19,15,22)(12,20,17,24)(9,12)(10,11)(13,20)(14,17)(15,18)(16,19)(21,22)(23,24)(25,27,29,34)(26,31,30,37)(28,35,36,33)(32,40,38,39)(9,11)(10,17)(12,18)(13,19)(14,15)(16,24)(20,21)(22,23)(25,28,29,36)(26,32,30,38)(27,33,34,35)(31,39,37,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.